Massive Volume Drop on Fuzz Face (HELP PLEASE)

[dmforte]

I built a fuzz face from this schematic: http://www.generalguitargadgets.com/pdf/ggg_ff5_sc_npn.pdf?phpMyAdmin=78482479fd7e7fc3768044a841b3e85a

Initially things were going well, the pedal sounded solid for about a week. After this, I began trying different transistors to see what sounded good. That's when the volume became volatile.

For example: I turn on the amp, test the guitar and it would be very loud when clean. Engage the pedal and there is a huge volume drop (perhaps a tenth the sound output, this did not occur before). Typically that's all, but occasionally there will be jump in volume that rises until I shut the amp off.

I am new to building pedals, but I have plenty guitar experience and plenty EE experience, if anyone has thoughts about what might be going wrong I would be tremendously appreciative.

[lonewolf]

sounds like a intermittent problem..are the transistors socketed? you could try the wiggle test to look for a solder joint going cold..I have had sockets going loose also ...especially if you swap parts a lot

[LucifersTrip]

first thing to do is check the transistor voltages when the volume is good and when there's a drop and compare. if you can't get "good" vol anymore, at least  take all voltages and compare em to what they should be  (~4.5v on Q2C, etc...)

basically, you want to know if it's the circuit or offboard

that being said, i've had that exact same problem with cheap jacks...a poor connection will do exactly that

[dmforte]

Thank you to both of you who replied, I set aside two hours since I posted and waged war against this circuit.

I went about it in the most unscientific manner and changed all the variables at once: several of the wires going into/out of  the jacks were somewhat frayed from some earlier problem solving on the board when I took it in and out a few times, I reskinned/resoldered them; resoldered nearly all the board connections; my transistors are in sockets, so I bent the transistor out and ensured good connections to all leads (ohm-meter); I found what believe was the root cause late in the campaign when I stumbled across two wires going into the volume pot which had apparently had their sheaths melt a bit (in a very inconspicuous way-picture two hands intertwined) due to some highly amateur soldering from me, effectively shorting the volume pot entirely if the pedal was jiggled in the right way.